The present invention relates to a windshield wiper apparatus for a motor vehicle, with a wiper motor and with at least one wiper bearing in which a wiper shaft is mounted, the wiper shaft being drivable by means of the wiper motor in order to actuate a wiper arm connected to the wiper shaft, wherein the wiper bearing has a bearing pin for receiving a tubular support, said bearing pin being fixable to the tubular support by means of a crimp, and to a method for the production of said windshield wiper apparatus.
Windshield wiper apparatuses of this type are known in general. During the crimping operation, the components to be fixed to one another are exposed to a very large deformation force in order to produce an interlocking connection between the bearing pin and the tubular support. In the process, in addition to the tubular support, regions of the material of the bearing pin are also plastically deformed in order to obtain an appropriately interlocking connection between the tubular support and the bearing pin. However, this may result in the material of the bearing pin being exposed to very large stresses precisely in the region of the crimp of the connection partners, which may result in adverse effects on the structure of the material or even in material fatigue.
In order to reduce the force to be applied during the crimping in order to ensure an interlocking connection between the bearing pin and tubular support, it is proposed in the prior art to form crimping pockets, for example, on two mutually opposite side regions of the bearing pin in the region of overlap with the tubular support which is to be plugged onto said bearing pin and is to be fastened thereto, the geometrical dimensions of which crimping pockets substantially correspond to the dimensions of the crimping tools. After the tubular support has been plugged on, the crimping tools are actuated such that subsections of the tubular support are moved into the crimping pockets in the bearing pin and are plastically deformed for fixing to the bearing pin. For this purpose, the tubular support, for example a steel tube, is deformed from the outside by the crimping tools, in particular by the crimping punches thereof, in such a manner that said support is moved by a type of deep drawing into the crimping pockets and forms an interlocking connection with the crimping pockets in the bearing pin.
A disadvantage of this method is that, due to the plastic deformation of the tubular support, a very great material loading of the bearing pin occurs precisely in the edge regions of the crimping pockets in the bearing pin. This results in stress peaks which may result in internal stresses in the respective workpieces or even in fatigue of the heavily loaded material of the bearing pin, and possibly even in the edge regions of the crimping pockets breaking off. Furthermore, a precise alignment of the crimping tools with the crimping pockets is necessary. However, this is very difficult, since, in the fitted state of the bearing pin and tubular support, the crimping pockets formed on the bearing pin are not visible from the outside.
Since the material of the tubular support is generally steel and therefore requires a higher deformation force than the bearing pin material which is inserted thereon and is generally produced from aluminum, zinc or plastic, it is also not possible to measure a significant increase in force upon deformation of the bearing pin during the crimping operation. Force-controlled crimping on the basis of the different material behavior is therefore possible only with difficulty, and therefore a pure displacement control has to be used for the crimping operation, which is associated with a further increased risk of introducing stress peaks into the bearing pin, in particular in the event of excessive crimping forces.
It is therefore the object of the present invention to provide a windshield wiper apparatus and a connecting method, which provide a secure, interlocking connection between the bearing pin and tubular support, also with a reduced application of force and simple handling, and reduce or as far as possible avoid stress peaks in the connection partners.